title: Relationship between cerebrovascular dysautoregulation and arterial blood pressure in the premature infant.
abstract: OBJECTIVE
  To evaluate cerebrovascular autoregulation as a function of arterial blood pressure (ABP) in the critically ill, premature infant.
  
  
  METHODS
  A prospective observational pilot study was conducted in two tertiary care Neonatal Intensive-Care Units. Premature infants (n=23, ≤30 weeks estimated gestational age with invasive ABP monitoring) were enrolled and received routine care while undergoing continuous autoregulation monitoring, using the cerebral oximetry index (COx). The COx is a moving, linear correlation coefficient between cortical reflectance oximetry and ABP. COx values were stratified as a function of ABP for individual subject recordings and for the cohort.
  
  
  RESULTS
  The mean duration of autoregulation monitoring was 3.2 days (median: 2.97, range: 0.61-3.99). A total of 10 of 23 (43%) developed intraventricular hemorrhage and 1 of 23 (4%) developed periventricular leukomalacia by head ultrasound. No association was found between neurologic injury and percentage of the monitoring periods with autoregulation impairment (defined as COx>0.5). Lower ABP was associated with dysautoregulation (higher COx values, P<0.01). The percentage of time with impaired autoregulation was greater with lower ABP (P=0.013, Spearman r=0.51).
  
  
  CONCLUSIONS
  All infants studied had periods with intact and periods with impaired cerebrovascular autoregulation, measured with the COx. Low ABP was associated with impaired autoregulation.
authors.affiliation: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Gilmore
authors.forename: B S
authors.initials: BS
authors.lastname: Stone
authors.forename: J A
authors.initials: JA
authors.lastname: Shepard
authors.forename: M
authors.initials: M
authors.lastname: Czosnyka
authors.forename: R B
authors.initials: RB
authors.lastname: Easley
authors.forename: K M
authors.initials: KM
authors.lastname: Brady
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D002245:Carbon Dioxide / Q000097:blood; D002543:Cerebral Hemorrhage / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D007235:Infant, Premature, Diseases / Q000503:physiopathology; D019102:Infant, Very Low Birth Weight; D007969:Leukomalacia, Periventricular / Q000503:physiopathology; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen